Hermetic compressor and vapor compression-type refrigeration cycle device including the hermetic compressor

ABSTRACT

A hermetic compressor, includes: a hermetic container storing a lubricating oil; an electric motor; a drive shaft; a compression mechanism; a rotary pressure increasing mechanism increasing pressure of refrigerant gas; a cylindrical lateral wall partitioning a space above the electric motor into outer and inner spaces; and a discharge pipe allowing refrigerant to flow out from the inner space into an external circuit. The refrigerant gas discharged from the compression mechanism into the hermetic container is moved from a space below the electric motor up to an upper end of the rotator through rotator vents of the rotator, flows into the rotary pressure increasing mechanism to be increased in pressure, flows into the inner space to increase a pressure in the inner space, and is discharged to an outside through the discharge pipe while suppressing inflow of the refrigerant gas from the outer space to the inner space.

TECHNICAL FIELD

The present invention relates to a hermetic compressor, and a vaporcompression-type refrigeration cycle device including the hermeticcompressor. In particular, the present invention relates to a hermeticcompressor excellent in oil separation effect, and a vaporcompression-type refrigeration cycle device including the hermeticcompressor.

BACKGROUND ART

Hitherto, in a refrigerant compressor used in vapor compression-typerefrigeration cycle devices (such as heat pump equipment andrefrigeration cycle equipment), a rotational force of an electric motoris transmitted to a compression mechanism by a drive shaft so thatrefrigerant gas is compressed. In such a refrigerant compressor, therefrigerant gas compressed by the compression mechanism is dischargedinto a hermetic container, moved from a space below the electric motorinto a space above the same through electric motor unit gas passages,and then discharged into a refrigerant circuit on an outside of thehermetic container. At this time, lubricating oil supplied to thecompression mechanism and mixed with the refrigerant gas is dischargedto the outside of the hermetic container. Hitherto, there is a problemin that an increase in amount of the oil to be discharged into therefrigerant circuit causes degradation in performance of a heatexchanger. In addition, there is another problem in that a decrease inamount of the oil stored in the hermetic container causes insufficientlubrication, resulting in degradation in reliability of the refrigerantcompressor.

In recent years, there have been promoted development of refrigerantcompressors having smaller sizes, and conversion to use of alternativerefrigerants (including natural refrigerant) having a lowerenvironmental load. Under the circumstances, advanced technology forseparating the oil in the hermetic container has been demanded. However,how the refrigerant and the lubricating oil flow and how the oilseparation occurs during high speed rotation of the electric motor inthe hermetic container are significantly complicated, and observationexperiments in the hermetic container under high pressure are not easy.Thus, there are a large number of unknown factors, and a large number oftechnical problems have not yet been solved.

In the high-pressure shell type scroll compressor disclosed in PatentLiterature 1, sucked refrigerant is compressed by the compressionmechanism arranged on an upper side in the hermetic container, and oncecaused to flow down to an oil reservoir at a bottom of the hermeticcontainer. After that, the refrigerant is caused to flow up from a spacebelow the electric motor to a space above the same through electricmotor gas passages, and then discharged as high pressure gas through adischarge pipe of the compressor. The high-pressure shell type scrollcompressor disclosed in Patent Literature 1 includes a fan arranged onan upper portion of a rotator of the electric motor, and partition wallsfor separating a stator side of the electric motor and a rotator side ofthe electric motor from each other above the fan. Then, the refrigerantand the lubricating oil are separated from each other by using acentrifugal force generated by rotation of the fan and by using pressureresistance generated through gaps between the partition walls. Thelubricating oil is prevented from flowing directly into the dischargepipe without being separated from the refrigerant, in other words, thelubricating oil is prevented from flowing out from the hermeticcontainer.

Further, in Patent Literature 2, there is disclosed an oil separationdevice for a hermetic electric compressor including: an electriccomponent housed in an upper portion of a hermetic container; acompression component that is driven by the electric component; an oilseparation plate arranged to face an upper end ring of a rotor of theelectric component across a predetermined clearance; and stirring vanesarranged upright to the oil separation plate, in which the stirringvanes are arranged upright only to a lower surface of the oil separationplate.

Effects of improving an oil separation condition in the hermeticcontainer of the compressor by using the fan and the partition walls inPatent Literature 1 and the oil separation plate and the stirring vanesin Patent Literature 2 are generally observed.

Further, in recent years, by using significantly advancedthree-dimensional fluid simulation technology, flow conditions of therefrigerant and the lubricating oil in the hermetic container of thecompressor can be visualized. Thus, new findings are obtained.Specifically, in Patent Literature 3, there is disclosed a refrigerantcompressor in which an increase in head pressure that is generated neara leading end in a rotation direction of an upper balance weight at anupper end of the rotator of the electric motor arranged in the hermeticcontainer is used to form an oil return passage from a vicinity of aleading end portion toward a lower end so that high density lubricatingoil that appears around the rotator is returned below the electricmotor, to thereby prevent the oil from flowing out.

CITATION LIST Patent Literature

-   Patent Literature 1: Japanese Patent No. 3925392-   Patent Literature 2: Japanese Unexamined Utility Model Application    Publication No. Hei 5-61487-   Patent Literature 3: Japanese Unexamined Patent Application    Publication No. 2009-264175

Non Patent Literature

-   Non Patent Literature 1: “Turbofan and compressor”, Corona    Publishing Co., Ltd. (1988)-   Non Patent Literature 2: “Fluid mechanical engineering”, Corona    Publishing Co., Ltd. (1983)

SUMMARY OF INVENTION Technical Problem

In general, to provide a high-performance centrifugal air-sendingdevice, as described in Non Patent Literature 1, the shape of theimpeller itself, the shape of the passage of flow extending into theimpeller, the shape of the passage of flow extending outside of theimpeller, and the like need to be theoretically designed.

However, in Patent Literatures 1 and 2, no theoretical design methodsare disclosed for the fan and the vanes that are each attached on theupper portion of the rotator (rotor) of the electric motor disclosedtherein, and optimum configurations for the fan and the vanes forimproving the oil separation condition have not yet been specified.

Specifically, in the high-pressure shell type scroll compressordisclosed in Patent Literature 1, unless the fan and the partition wallsto be attached on the upper portion of the rotator of the electric motorare appropriately designed and arranged, the fan and the partition wallscannot prevent the refrigerant, which flows from the compressionmechanism into the space above the electric motor (refrigerant mixedwith fine oil particles), from flowing from the stator side of theelectric motor directly into the rotator side of the electric motor.Thus, there is a problem in that the oil separation effect cannot befully exerted.

The present invention has been made to solve the problem as describedabove, and it is an object thereof to provide a hermetic compressorcapable of reducing an amount of oil flowing to an outside of a hermeticcontainer than that in the related art by using rotation of a rotator ofan electric motor arranged in the hermetic container, and to provide avapor compression-type refrigeration cycle device including the hermeticcompressor.

Solution to Problem

According to one embodiment of the present invention, there is provideda hermetic compressor, including: a hermetic container having a bottomportion for storing lubricating oil; an electric motor arranged in thehermetic container, the electric motor including: a stator and a rotatorthrough which a rotator vent is formed in a vertical direction; a driveshaft attached to the rotator; a compression mechanism arranged in thehermetic container, for compressing refrigerant by using rotation of thedrive shaft; a rotary pressure increasing mechanism arranged on an upperportion of the rotator, for increasing a pressure of refrigerant gas byallowing the refrigerant gas to flow through the rotary pressureincreasing mechanism while rotating about the drive shaft; a cylindricallateral wall for partitioning a space above the electric motor into anouter space on the stator side and inner space on the rotator side insuch a manner that the cylindrical lateral wall surrounds the rotarypressure increasing mechanism positioned in the inner space; and adischarge pipe communicated to the inner space, for allowing therefrigerant to flow out from the inner space into an external circuitthat is external to the hermetic container, in which the refrigerant gasthat is compressed by the compression mechanism and discharged into thehermetic container is moved from a space below the electric motor up toan upper end of the rotator through the rotator vents, flows into therotary pressure increasing mechanism to be increased in pressure, flowsinto the inner space to increase a pressure in the inner space, and isdischarged to an outside through the discharge pipe while suppressinginflow of the refrigerant gas from the outer space to the inner space.

Further, according to one embodiment of the present invention, there isprovided a vapor compression-type refrigeration cycle device, including:the hermetic compressor of the one embodiment of the present invention;a radiator for transferring heat of refrigerant that is compressed bythe hermetic compressor; an expansion mechanism for expanding therefrigerant that flows out from the radiator; and an evaporator forcausing the refrigerant that flows out from the expansion mechanism toreceive heat.

Advantageous Effects of Invention

The one embodiment of the present invention can prevent a decrease inamount of lubricating oil stored in the hermetic container and canobtain an effect of suppressing reliability degradation to be caused byinsufficient lubrication, and an effect of achieving high energy-savingperformance.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a vertical sectional view of a structure of a hermeticcompressor according to Embodiment 1 of the present invention.

FIG. 2 is a horizontal sectional view of the structure of the hermeticcompressor according to Embodiment 1 of the present invention (sectionalview taken along the line A-A in FIG. 1).

FIG. 3 is a perspective view of a rotary pressure increasing mechanismthat is arranged on an upper portion of a rotator of the hermeticcompressor according to Embodiment 1 of the present invention.

FIG. 4 is a vertical sectional view of a structure of a hermeticcompressor according to Embodiment 2 of the present invention.

FIG. 5 is a horizontal sectional view of the structure of the hermeticcompressor according to Embodiment 2 of the present invention (sectionalview taken along the line A-A in FIG. 4).

FIG. 6 is a perspective view of a rotary pressure increasing mechanismthat is arranged on an upper portion of a rotator of the hermeticcompressor according to Embodiment 2 of the present invention.

FIG. 7 is a vertical sectional view of a structure of a hermeticcompressor according to Embodiment 3 of the present invention.

FIG. 8 is a horizontal sectional view of the structure of the hermeticcompressor according to Embodiment 3 of the present invention (sectionalview taken along the line A-A in FIG. 7).

FIG. 9 is a vertical sectional view of a structure of a hermeticcompressor according to Embodiment 4 of the present invention.

FIG. 10 is a horizontal sectional view of the structure of the hermeticcompressor according to Embodiment 4 of the present invention (sectionalview taken along the line A-A in FIG. 9).

FIG. 11 is a perspective view of a rotary pressure increasing mechanismthat is arranged on an upper portion of a rotator of the hermeticcompressor according to Embodiment 4 of the present invention.

FIG. 12 is a configuration diagram of a vapor compression-typerefrigeration cycle device according to Embodiment 5 of the presentinvention.

DESCRIPTION OF EMBODIMENTS Embodiment 1

FIG. 1 is a vertical sectional view of a structure of a hermeticcompressor according to Embodiment 1 of the present invention. FIG. 2 isa horizontal sectional view of the structure of the hermetic compressoraccording to Embodiment 1 of the present invention (sectional view takenalong the line A-A in FIG. 1). Further, FIG. 3 is a perspective view ofa rotary pressure increasing mechanism that is arranged on an upperportion of a rotator of the hermetic compressor according to Embodiment1 of the present invention. Note that, the solid arrow shown in FIG. 2indicates a rotation direction of the rotary pressure increasingmechanism. Further, the rotary pressure increasing mechanism illustratedin FIG. 3 is viewed in a direction of the three-dimensional arrow shownin FIG. 2.

First, with reference to FIGS. 1 to 3, a fundamental structure andoperation of a hermetic compressor 100 according to Embodiment 1 isdescribed.

<Fundamental structure and operation of hermetic compressor 100>

The hermetic compressor 100 according to Embodiment 1 is a high-pressureshell hermetic scroll compressor, which includes a hermetic container 1having a bottom portion in which a lower oil reservoir 2 for storinglubricating oil is formed, and an electric motor 8, a drive shaft 3, acompression mechanism 60, and a rotary pressure increasing mechanism 49that are housed in the hermetic container 1.

The electric motor 8 includes a substantially cylindrical stator 7having an inner peripheral portion through which a through-hole isformed in a vertical direction, and a substantially cylindrical rotator6 arranged on an inner peripheral side of the stator 7 across apredetermined air gap 27 a. The electric motor 8 according to Embodiment1 is, for example, a DC brushless motor. The stator 7 is formed oflaminated steel plates, and includes a core 7 c that is formed into awound coil block by winding a coil therearound at a high density.Further, at an upper end of the stator 7, coil parts projecting from thewound coil block toward an upper side of the stator 7, that is, aplurality of electric motor upper coil-interconnecting portion 7 a areformed. At a lower end of the stator 7, coil parts projecting from thewound coil block toward a lower side of the stator 7, that is, aplurality of electric motor lower coil-interconnecting portions 7 b areformed. This stator 7 is attached to an inner peripheral surface of thehermetic container 1 by press fitting, welding, and the like. Note that,an outer peripheral portion of the core 7 c of the stator 7 is partiallycut out so that stator outer peripheral passages 25 are formed betweenthe core 7 c and the hermetic container 1 under a state in which thestator 7 is attached to the inner peripheral surface of the hermeticcontainer 1.

The rotator 6 is formed by laminating steel plates and sandwichinguppermost and lowermost ones of the laminated steel plates respectivelywith a rotator upper end fixing substrate 33 and a rotator lower endfixing substrate 34. Further, magnets are arranged in the rotator 6.Still further, respectively on an upper surface of the rotator upper endfixing substrate 33 and a lower surface of the rotator lower end fixingsubstrate 34, an upper balance weight 31 and a lower balance weight 32,which have a predetermined thickness and are arranged in reverse phases,are arranged along outer rims of the rotator 6. Yet further, fourrotator vents 26 are formed in the vertical direction through therotator 6 according to Embodiment 1. Note that, the number of therotator vents 26 is not particularly limited as long as at least onerotator vent 26 is formed.

A lower end portion of the drive shaft 3 is attached to the rotator 6 ofthe electric motor 8, and an upper end portion thereof is attached tothe compression mechanism 60 described below. In other words, the driveshaft 3 is configured to transmit a driving force of the electric motor8 to the compression mechanism 60. An upper side of the drive shaft 3 isheld in a freely rotatable manner by a main bearing unit 55 of an upperbearing member 11 arranged above the electric motor 8, and a lower sidethereof is held in a freely rotatable manner by a sub bearing unit 54 ofa lower bearing member 12 arranged below the electric motor 8.

The compression mechanism 60 is arranged above the electric motor 8, andincludes a fixed scroll 51 and an orbiting scroll 52. Plate-like scrollteeth are formed on a lower surface of the fixed scroll 51, which isattached to a compression mechanism casing 50 that is fixed to the innerperipheral surface of the hermetic container 1. Plate-like scroll teethto mesh with the plate-like scroll teeth of the fixed scroll 51 areformed on an upper surface of the orbiting scroll 52, which is providedin a freely slidable manner at the upper end portion of the drive shaft3. When the plate-like scroll teeth of the fixed scroll 51 and theplate-like scroll teeth of the orbiting scroll 52 mesh with each other,compression chambers 4 are formed between the plate-like scroll teeth onboth sides. A lower surface of the orbiting scroll 52 is supported in afreely slidable manner by an upper surface portion of the upper bearingmember 11. An outer peripheral surface of the upper bearing member 11 issupported in a freely slidable manner by an inner peripheral surface ofthe compression mechanism casing 50. With this configuration, the upperbearing member 11 can be retracted downward in response to applicationof pressure of a predetermined value or more in the compression chamber4, and thus an abnormal pressure increase in the compression chamber 4can be avoided.

Note that, a refrigerant passage 57 is formed between an outerperipheral portion of the compression mechanism casing 50 and thehermetic container 1. Further, a discharge cover 56 for partitioning anelectric motor superjacent space 9 (more specifically, upper part of acylindrical lateral wall 37 described below) into an electric motorstator superjacent space 9 a (outer space) and an electric motor rotatorsuperjacent space 9 b (inner space) is arranged under the compressionmechanism casing 50.

The rotary pressure increasing mechanism 49 is arranged on an upperportion of the rotator 6. The rotary pressure increasing mechanism 49according to Embodiment 1 is a centrifugal impeller 40, which includes aplurality of vanes 41 arranged in a manner of extending from an innerperipheral side to an outer peripheral side about the drive shaft 3.Further, the centrifugal impeller 40 according to Embodiment 1 alsoincludes a vane superjacent disk 43 (upper surface plate) for blockinginflow of refrigerant gas from above the vanes 41 into the centrifugalimpeller 40, and a vane subjacent disk 44 (lower surface plate) forblocking inflow of refrigerant gas from below the vanes 41 into thecentrifugal impeller 40. Further, to prevent inflow of refrigerant gasthrough passages other than the rotator vents 26 into an inlet on aninner peripheral side of the centrifugal impeller 40, an innerperipheral flow guide 42 (partition plate) is extended downward from arim of an opening portion of the vane subjacent disk 44, which is formedat a position on an inner peripheral side of the vanes 41, in a mannerthat an outer peripheral portion of the rotator vents 26 is surrounded.The centrifugal impeller 40 is rotated about the drive shaft 3 through,for example, connection between the drive shaft 3 and the vanesuperjacent disk 43, connection between the cylindrical lateral wall 37described below and the vane subjacent disk 44, or connection betweenthe rotator 6 and the inner peripheral flow guide 42. With thisconfiguration, the refrigerant that flows in through the inlet on theinner peripheral side is increased in pressure and is caused to flow outthrough an outlet on the outer peripheral side.

Further, in the hermetic compressor 100 according to Embodiment 1, thecylindrical lateral wall 37 is arranged to surround the centrifugalimpeller 40 (more specifically, refrigerant outlet on the outerperipheral side), in other words, to partition the electric motorsuperjacent space 9 into the electric motor stator superjacent space 9 a(outer space) and the electric motor rotator superjacent space 9 b(inner space). Further, in the cylindrical lateral wall 37, an oil drainhole 39 is formed on a rotation direction leading end portion 31 a sideof the upper balance weight 31. This cylindrical lateral wall 37 isattached to an upper surface portion of a disk portion 38 a of abalancer fixing bottom plate 38 for fixing the upper balance weight 31to the rotator upper end fixing substrate 33. Further, in Embodiment 1,a stator inner peripheral passage closing portion 38 b (closing member)is arranged to project from an outer peripheral portion of the diskportion 38 a of the balancer fixing bottom plate 38. This stator innerperipheral passage closing portion 38 b is arranged to close an upperpart of a stator inner peripheral passage 27 formed between the rotator6 and the stator 7 (specifically, air gap 27 a between the rotator 6 andthe stator 7, and core inner peripheral portion cut-out passage 27 bformed by cutting out the inner peripheral side of the stator 7).

In the hermetic compressor 100 configured as described above, theorbiting scroll 52 of the compression mechanism 60 performs eccentricorbital operation along with rotation of the drive shaft 3, causingsucked low-pressure refrigerant to enter the compression chamber 4through a compressor suction pipe 21. Then, the sucked pressurerefrigerant is increased in pressure through a compression step ofgradually decreasing a volume of the compression chamber 4, and isdischarged into a discharge space 10 ((1) in FIG. 1) in the hermeticcontainer 1 through a discharge port 18 of the fixed scroll 51.

Further, along with the rotation of the drive shaft 3, the lubricatingoil stored in the lower oil reservoir 2 is sucked upward from a lowerend of the drive shaft 3, and flows into a hollow hole 3 a. Part of thelubricating oil is supplied, for example, to the sub bearing unit 54 andthe main bearing unit 55 through oil supply holes (not shown). Further,part of the lubricating oil flows out from an upper end of the driveshaft 3, and then is supplied into the compression chamber 4 through,for example, a gap between the upper bearing member 11 and the orbitingscroll 52 and an oil supply hole 3 b, increasing effects of lubricationof the compression mechanism 60 and sealing of the compressed gas. Thelubricating oil that is supplied in the compression chamber 4 isdischarged into the discharge space 10 ((1) in FIG. 1) in the hermeticcontainer 1 through the discharge port 18 of the fixed scroll 51together with the refrigerant compressed to have a high pressure in thecompression chamber 4.

<Flow of Refrigerant in Hermetic Container>

The refrigerant that is discharged through the discharge port 18 flowsdownward through the refrigerant passage 57 formed of a gap between anouter peripheral side of the compression mechanism casing 50 and thehermetic container 1, and reaches the electric motor stator superjacentspace 9 a ((2) in FIG. 1). Further, this refrigerant flows downward intoan electric motor stator subjacent space ((3) in FIG. 1) in an electricmotor subjacent space 5 through the stator outer peripheral passages 25formed between the core 7 c of the stator 7 and the hermetic container1, and reaches the lower bearing member 12 including the sub bearingunit 54. During this process, the refrigerant and the lubricating oilmixed in an atomized form with the refrigerant are separated from eachother, and the separated lubricating oil is refluxed to the lower oilreservoir 2 through an oil return hole 12 a formed through the lowerbearing member 12.

Meanwhile, the refrigerant that flows in the electric motor statorsubjacent space in the electric motor subjacent space 5 flows up from anelectric motor rotator subjacent space ((4) in FIG. 1) in the electricmotor subjacent space 5 through the rotator vents 26 into a vane innerpassage 46 of the centrifugal impeller 40 attached on an upper portionof the rotator 6 (passage on an inner peripheral side of the innerperipheral flow guide 42, that is, space represented by (5) in FIG. 1).Then, the refrigerant that flows in the vane inner passage 46 is suckedinto inter-vane passages 47 formed between the vanes 41 of thecentrifugal impeller 40, flows to the outer peripheral side while beingincreased in pressure in accordance with a rotational speed of thecentrifugal impeller 40, and, on an outer peripheral side of the vanes41, flows up through a vane outer passage 48 formed in a region on aninner peripheral side of the cylindrical lateral wall 37. Then, thisrefrigerant is once released into the electric motor rotator superjacentspace 9 b ((6) in FIG. 1) that is formed above the circular vanesuperjacent disk 43 covering upper surfaces of the vanes 41 of thecentrifugal impeller 40 and on the inner peripheral side of thecylindrical lateral wall 37. With this, static pressure is increased.After that, the refrigerant that flows in the electric motor rotatorsuperjacent space 9 b ((6) in FIG. 1) flows into the discharge cover 56through an opening portion 56 a of the discharge cover 56, and then isdischarged into an external circuit on an outside of the hermeticcontainer 1 through a compressor discharge pipe 22 that communicates toan inner space of the discharge cover 56.

<Flow in Short Circuit Passage 23 and Short-Circuit Prevention>

To prevent electrical short-circuiting between the electric motor uppercoil-interconnecting portions 7 a and the discharge cover 56, a gapbetween the electric motor upper coil-interconnecting portions 7 a andthe discharge cover 56, that is, a short circuit passage 23 needs to beformed. Thus, during the process from the discharge space 10 ((1) inFIG. 1) to the electric motor rotator superjacent space 9 b ((6) in FIG.1), the refrigerant may flow from the electric motor stator superjacentspace 9 a ((2) in FIG. 1) directly into the electric motor rotatorsuperjacent space 9 b ((6) in FIG. 1) without flowing through theelectric motor stator subjacent space ((3) in FIG. 1). As a result, alarge number of droplets of unseparated oil may flow out from thehermetic container 1 to the external circuit, which may causedegradation in performance and reliability of the hermetic compressor100, and degradation in performance of the vapor compression-typerefrigeration cycle device (in particular, of the heat exchanger).

In view of the circumstances, to reduce an amount of the flow of therefrigerant that short-circuits to be directly discharged through theshort circuit passage 23, the following measures need to be taken.

(1) Set a passage resistance of the short circuit passage 23 to theelectric motor rotator superjacent space 9 b ((6) in FIG. 1) to besufficiently high.

(2) Increase a pressure in the electric motor rotator superjacent space9 b ((6) in FIG. 1) to be close to or higher than a pressure in theelectric motor stator superjacent space 9 a.

Thus, in Embodiment 1, the cylindrical lateral wall 37 is arrangedupright to the balancer fixing bottom plate 38 so that a passage area ofthe short circuit passage 23 is reduced, and thus the passage resistanceis increased. Further, a lower end portion of the discharge cover 56 isbent so that a passage shape of the short circuit passage 23 is madecomplicated, and thus the passage resistance of the short circuitpassage 23 is further increased.

In addition, in Embodiment 1, the cylindrical lateral wall 37 isinterposed to separate the centrifugal impeller 40 arranged on therotator 6 and the electric motor upper coil-interconnecting portions 7 afrom each other. With this, the refrigerant gas that is increased inpressure by the centrifugal impeller 40 can be suppressed from reverselyflowing into the electric motor stator superjacent space 9 a ((2) inFIG. 1) through radial passages 28 in the electric motor uppercoil-interconnecting portions 7 a. As a result, the pressure in theelectric motor rotator superjacent space 9 b ((6) in FIG. 1) can beincreased.

Note that, other than the rotator vents 26, the stator inner peripheralpassage 27 (air gap 27 a and core inner peripheral portion cut-outpassage 27 b) is formed as an upward refrigerant passage from theelectric motor subjacent space 5 ((3) or (4) in FIG. 1) to the electricmotor superjacent space 9 ((2) or (5) in FIG. 1), and the pressureincreasing effect by the centrifugal impeller 40 cannot be exerted tothe refrigerant gas that flows through the stator inner peripheralpassage 27. Therefore, a greater pressure increasing effect can beobtained by the centrifugal impeller 40 when the stator inner peripheralpassage 27 is closed as much as possible. Thus, in Embodiment 1, toslightly increase an outer diameter of the balancer fixing bottom plate38 (for example, approximately 1 mm), the stator inner peripheralpassage closing portion 38 b is arranged to the outer peripheral portionof the disk portion 38 a so that the upper part of the stator innerperipheral passage 27 is closed. With this, an amount of the refrigerantgas that flows through the stator inner peripheral passage 27 can besuppressed, and thus the pressure in the electric motor rotatorsuperjacent space 9 b ((6) in FIG. 1) can be further increased.

<Design of Centrifugal Impeller>

To increase the pressure in the electric motor rotator superjacent space9 b ((6) in FIG. 1) with the centrifugal impeller 40 such thatapproximately 100% of the refrigerant flows from the electric motorstator superjacent space 9 a ((2) in FIG. 1) to the electric motorstator subjacent space ((3) in FIG. 1), the shape of the vanes and thepassages of the centrifugal impeller 40 need to be designed such that apressure (P₆) in the electric motor rotator superjacent space 9 b ((6)in FIG. 1) is higher than a pressure (P₂) in the electric motor statorsuperjacent space 9 a ((2) in FIG. 1). Further, to increase a pressurein the centrifugal impeller 40, input to the compressor (electric powerconsumption thereof) is increased. Thus, it is also important to designa highly-efficient centrifugal impeller 40.

According to Non Patent Literature 2 (p. 132), of centrifugal fans, aturbofan (having vanes that are formed rearward with respect to arotation direction) is advantageous in terms of efficiency. Thus, theshape of the vanes 41 of the centrifugal impeller 40 is determined to berearward with respect to the rotation direction, and eight vanes 41formed into this shape are arranged in axial symmetry with respect tothe drive shaft 3. Further, an inlet angle of each of the vanes 41 isdetermined such that the vanes 41 each form an angle within a range of±5 degrees with respect to a circle formed by connecting end positionson the inner peripheral side of the vanes 41. This is because, accordingto Non Patent Literature 1 (p. 216), a collision loss occurs when anentry angle ib that is equal to a difference between a relative inflowangle 131 and a vane inlet angle β1 b at an inlet of the impeller rangesfrom 2 degrees to 5 degrees or more, causing losses in the compressor.Note that, to increase a percentage by which the refrigerant that flowsthrough the rotator vents 26 flows into the inner peripheral side of thecentrifugal impeller 40, and then flows out to the outer peripheral sidethereof (passage rate), the following configurations are devised.

-   -   The rotator vents 26 are arranged on an inner side with respect        to the inner peripheral flow guide 42 in plan view.    -   The vane superjacent disk 43 and the vane subjacent disk 44 for        covering the upper and lower sides of the vanes 41 are        configured to cover all over the inner peripheral side to the        outer peripheral side of the plurality of vanes 41.

With this, the pressure increasing effect by the centrifugal impeller 40can be further increased, and the pressure in the electric motor rotatorsuperjacent space 9 b ((6) in FIG. 1) can be further increased.

<Effects>

In the hermetic compressor 100 configured as in Embodiment 1, thepressure in the electric motor rotator superjacent space 9 b ((6) inFIG. 1) can be increased by using rotation of the rotator 6 in thehermetic container 1. Specifically, when the hermetic compressor 100that is configured to output three horsepower and operated at a constantspeed (50 rps), is operated by using a refrigerant R22 under thecondition of Ashrae standard, an effect of increasing the pressure inthe electric motor rotator superjacent space 9 b ((6) in FIG. 1) inunits of several kPa can be obtained. As a result, the refrigerant isless liable to flow from the electric motor stator superjacent space 9 a((2) in FIG. 1) directly into the electric motor rotator superjacentspace 9 b ((6) in FIG. 1) through the short circuit passage 23, and thelarge number of droplets of the unseparated oil are less liable to flowout from the hermetic container 1 to the external circuit. Further, toeffectively use the sealed lubricating oil, an effect of suppressing thedegradation in performance of the hermetic compressor 100, and an effectof suppressing the degradation in reliability thereof due toinsufficient lubrication that may be caused by a decrease in amount ofthe oil stored in the hermetic container 1 can be obtained.

Embodiment 2

FIG. 4 is a vertical sectional view of a structure of a hermeticcompressor according to Embodiment 2 of the present invention. FIG. 5 isa horizontal sectional view of the structure of the hermetic compressoraccording to Embodiment 2 of the present invention (sectional view takenalong the line A-A in FIG. 4). Further, FIG. 6 is a perspective view ofa rotary pressure increasing mechanism that is arranged on an upperportion of a rotator of the hermetic compressor according to Embodiment2 of the present invention. Note that, the solid arrow shown in FIG. 5indicates a rotation direction of the rotary pressure increasingmechanism. Further, the rotary pressure increasing mechanism illustratedin FIG. 6 is viewed in a direction of the three-dimensional arrow shownin FIG. 5.

Now, with reference to FIGS. 4 to 6, the hermetic compressor 100according to Embodiment 2 is described. Note that, the fundamentalstructure and the operation of the hermetic compressor 100 according toEmbodiment 2 are the same as those in Embodiment 1, and hencedescription thereof is omitted.

(1) Embodiment 2 is different from Embodiment 1 in that only four of theeight vanes 41 of the centrifugal impeller 40 in Embodiment 1 that arepositioned on one side on which the upper balance weight 31 is absentare left, and that a height of each of the four vanes 41 is designed tobe equal to a height of the upper balance weight 31. In Embodiment 1, toallow the refrigerant flowing through the rotator vents 26 to flow outfrom the centrifugal impeller 40 through the vane inner passage 46, theinner peripheral flow guide 42 and the vane subjacent disk 44 areneeded. In contrast, in Embodiment 2, there is an advantage in that theinner peripheral flow guide 42 and the vane subjacent disk 44 can beomitted, and hence the centrifugal impeller 40 is easily processed.

Note that, in a case where the centrifugal impeller 40 is configured asin Embodiment 2, fan efficiency is lower than that of the centrifugalimpeller 40 according to Embodiment 1, in which the vanes 41 arearranged in axial symmetry. Further, in the case where the centrifugalimpeller 40 is configured as in Embodiment 2, pressure pulsation by thecentrifugal impeller 40 is increased in comparison with that by thecentrifugal impeller 40 according to Embodiment 1, in which the vanes 41are arranged in axial symmetry. As a result, vibration and noise mayoccur. Thus, in a case where the fan efficiency and prevention of thevibration and noise are regarded as important, it is preferred that thecentrifugal impeller 40 be configured as in Embodiment 1.

(2) In Embodiment 1, the cylindrical lateral wall 37 for preventingshort-circuit flow of the refrigerant through the short circuit passage23, and the balancer fixing bottom plate 38 for fixing the cylindricallateral wall 37 are formed as separate members. Meanwhile, in Embodiment2, the cylindrical lateral wall 37 and the balancer fixing bottom plate38 according to Embodiment 1 are provided as an oil separating cup 36obtained by a process of integrating a cylindrical lateral wall 36 a anda bottom plate 36 b with each other. Note that, similarly to Embodiment1, an oil drain hole 36 c is formed in the oil separating cup 36 on therotation direction leading end portion 31 a side of the upper balanceweight 31. When the oil separating cup 36 obtained by the process ofintegrating the cylindrical lateral wall 36 a and the bottom plate 36 bwith each other is provided instead of the cylindrical lateral wall 37and the balancer fixing bottom plate 38 according to Embodiment 1, thereis an advantage in that a process of assembling the hermetic compressor100 can be facilitated.

In this way, according to the hermetic compressor 100 configured as inEmbodiment 2, the decrease in amount of the lubricating oil stored inthe hermetic container 1 can be prevented. In addition, an effect ofsuppressing reliability degradation caused by insufficient lubricationand an effect of suppressing energy-saving performance degradation,which are comparably less than those in Embodiment 1 but are equivalentthereto, can be obtained. Meanwhile, according to the hermeticcompressor 100 configured as in Embodiment 2, there is an advantage inthat a manufacturing cost for the centrifugal impeller 40 is lower thanthat in Embodiment 1.

(3) Note that, other differences between the hermetic compressor 100according to Embodiment 2 and the hermetic compressor 100 described inEmbodiment 1 are as follows.

-   -   In the hermetic compressor 100 according to Embodiment 2, the        lower end portion of the discharge cover 56 is not subjected to        a bending process, and hence the short circuit passage 23 has a        simple shape. Thus, in the hermetic compressor 100 according to        Embodiment 2, the passage resistance in the short circuit        passage 23 is determined based on a size of a smallest gap that        is formed between the discharge cover 56 and the cylindrical        lateral wall 36 a.    -   Further, the hermetic compressor 100 according to Embodiment 2        does not include the closing member for closing the stator inner        peripheral passage 27 (counterpart of the stator inner        peripheral passage closing portion 38 b in Embodiment 1).

Embodiment 3

FIG. 7 is a vertical sectional view of a structure of a hermeticcompressor according to Embodiment 3 of the present invention. FIG. 8 isa horizontal sectional view of the structure of the hermetic compressoraccording to Embodiment 3 of the present invention (sectional view takenalong the line A-A in FIG. 7). Note that, the solid arrow shown in FIG.8 indicates a rotation direction of the rotary pressure increasingmechanism.

Now, with reference to FIGS. 7 and 8, the hermetic compressor 100according to Embodiment 3 is described. Note that, the fundamentalstructure and the operation of the hermetic compressor 100 according toEmbodiment 3 are the same as those in Embodiment 1, and hencedescription thereof is omitted.

(1) Similarly to Embodiment 2, in the centrifugal impeller 40 accordingto Embodiment 3, only four of the eight vanes 41 of the centrifugalimpeller 40 in Embodiment 1 that are positioned on the one side on whichthe upper balance weight 31 is absent are left, and the height of eachof the four vanes 41 is designed to be equal to the height of the upperbalance weight 31. However, the centrifugal impeller 40 according toEmbodiment 3 is different from that according to Embodiment 2 in thatthe vanes 41 are arranged in a radial direction (direction orthogonal tothe rotation direction of the drive shaft 3). With this, although fanefficiency is lower than that of the turbofan, there is an advantage inthat the centrifugal impeller 40 can be easily manufactured.

(2) In Embodiments 1 and 2, the cylindrical lateral wall (cylindricallateral wall 37 or cylindrical lateral wall 36 a) for preventing theshort-circuit flow of the refrigerant through the short circuit passage23 is arranged on the upper portion of the rotator 6 so that thecylindrical lateral wall is rotated together with the rotator 6. Incontrast, in Embodiment 3, a closing cover 29 (more specifically,cylindrical portion 29 a) as a counterpart of the cylindrical lateralwall is arranged on an inner side of the electric motor uppercoil-interconnecting portions 7 a of the stator 7 so that the radialpassages 28 are closed. Further, in the closing cover 29, on an innerperipheral side of the cylindrical portion 29 a, a projecting portion 29b for closing the upper part of the stator inner peripheral passage 27is formed. This projecting portion 29 b is a counterpart of the statorinner peripheral passage closing portion 38 b in Embodiment 1, and isdesigned such that a smallest gap 29 c between the projecting portion 29b and the disk portion 38 a of the balancer fixing bottom plate 38 isnarrowed (for example, approximately 1 mm to 2 mm) within a range inwhich electrical short-circuiting does not occur. Note that, in a casewhere this design is employed, a pressure increasing effect by rotationof the cylindrical lateral wall about the drive shaft cannot beobtained.

In this way, according to the hermetic compressor 100 configured as inEmbodiment 3, the decrease in amount of the lubricating oil stored inthe hermetic container 1 can be prevented. In addition, the effect ofsuppressing reliability degradation caused by insufficient lubricationand the effect of suppressing energy-saving performance degradation,which are comparably less than those in Embodiment 1 but are equivalentthereto, can be obtained.

Embodiment 4

FIG. 9 is a vertical sectional view of a structure of a hermeticcompressor according to Embodiment 4 of the present invention. FIG. 10is a horizontal sectional view of the structure of the hermeticcompressor according to Embodiment 4 of the present invention (sectionalview taken along the line A-A in FIG. 9). Further, FIG. 11 is aperspective view of a rotary pressure increasing mechanism that isarranged on an upper portion of a rotator of the hermetic compressoraccording to Embodiment 4 of the present invention. Note that, the solidarrow shown in FIG. 10 indicates a rotation direction of the rotarypressure increasing mechanism. Further, the rotary pressure increasingmechanism illustrated in FIG. 11 is viewed in a direction of thethree-dimensional arrow shown in FIG. 10.

Now, with reference to FIGS. 9 to 11, the hermetic compressor 100according to Embodiment 4 is described. Note that, the fundamentalstructure and the operation of the hermetic compressor 100 according toEmbodiment 4 are the same as those in Embodiment 1, and hencedescription thereof is omitted.

(1) The configuration of the hermetic compressor 100 according toEmbodiment 4 is the same as the configuration of the hermetic compressor100 described in Embodiment 2 except the configuration of the rotarypressure increasing mechanism 49. Specifically, the rotary pressureincreasing mechanism 49 according to Embodiment 4 is obtained byremoving all the vanes 41 from the centrifugal impeller 40 described inEmbodiment 1. In other words, the rotary pressure increasing mechanism49 according to Embodiment 4 includes an oil separating rotary disk 35as a counterpart of the vane superjacent disk 43 in Embodiment 1, and abalancer cover 30 including a rotary disk 30 b and an inner peripheralflow guide 30 c as respective counterparts of the vane subjacent disk 44and the inner peripheral flow guide 42 in Embodiment 1. In the rotarypressure increasing mechanism 49 configured in this way, the refrigerantthat flows out from the rotator vents 26 flows into an inner passage 30a formed on an inner peripheral side of the inner peripheral flow guide30 c, flows between the rotary disk 30 b and the oil separating rotarydisk 35, and flows out into the electric motor rotator superjacent space9 b ((6) in FIG. 9) through a cup inner passage 36 d formed on an innerperipheral side of the oil separating cup 36. In the rotary pressureincreasing mechanism 49 according to Embodiment 4, although the greatpressure increasing effect (for example, in units of several kPa) by thecentrifugal impeller cannot be obtained, a pressure increasing effect(for example, 1 kPa or less) can be obtained by rotations of the rotarydisk 30 b of the balancer cover 30, the oil separating rotary disk 35,and the cylindrical lateral wall 36 a of the oil separating cup 36.

In this way, according to the hermetic compressor 100 configured as inEmbodiment 4, the decrease in amount of the lubricating oil stored inthe hermetic container 1 can be prevented. In addition, the effect ofsuppressing reliability degradation caused by insufficient lubricationand the effect of suppressing energy-saving performance degradation,which are comparably less than (for example, less than half of) those inEmbodiment 1 but are equivalent thereto, can be obtained. Meanwhile,according to the hermetic compressor 100 configured as in Embodiment 4,there is an advantage in that a manufacturing cost for the rotarypressure increasing mechanism 49 is lower than that in Embodiment 1.

In Embodiments 1 to 4, the present invention is described with anexample of the high-pressure shell hermetic scroll compressor. In thiscontext, also when other rotary compression types (such as sliding-vanetype and swing type) are employed, the same effects as those inEmbodiments 1 to 4 can be obtained as long as the arrangement of therotator 6 and the stator 7 of the electric motor 8, and the flow of therefrigerant from the electric motor subjacent space 5 to the electricmotor superjacent space 9 are unchanged.

Embodiment 5

In Embodiment 5, an example of the vapor compression-type refrigerationcycle device including the hermetic compressor 100 described in any oneof Embodiments 1 to 4 is described.

FIG. 12 is a configuration diagram of a vapor compression-typerefrigeration cycle device 101 according to Embodiment 5. The vaporcompression-type refrigeration cycle device 101 includes the hermeticcompressor 100 described in any one of Embodiments 1 to 4, a radiator102 for transferring heat of the refrigerant compressed by the hermeticcompressor 100, an expansion mechanism 103 for expanding the refrigerantthat flows out from the radiator 102, and an evaporator 104 for causingthe refrigerant that flows out from the expansion mechanism 103 toreceive heat. When the hermetic compressor 100 according to any one ofEmbodiments 1 to 4 is used in the vapor compression-type refrigerationcycle device 101, the vapor compression-type refrigeration cycle device101 can be improved in energy saving efficiency, reduced in vibrationand noise, and increased in reliability.

REFERENCE SIGNS LIST

-   -   1 hermetic container 2 lower oil reservoir 3 drive shaft 3 a        hollow hole 3 b oil supply hole 4 compression chamber 5 electric        motor subjacent space 6 rotator 7 stator 7 a electric motor        upper coil-interconnecting portion 7 b electric motor lower        coil-interconnecting portion 7 c core 8 electric motor 9        electric motor superjacent space 9 a electric motor stator        superjacent space 9 b electric motor rotator superjacent space        10 discharge space 11 upper bearing member 12 lower bearing        member 12 a oil return hole 18 discharge port 21 compressor        suction pipe 22 compressor discharge pipe 23 short circuit        passage 25 stator outer peripheral passage 26 rotator vent 27        stator inner peripheral passage 27 a air gap 27 b core inner        peripheral portion cut-out passage 28 radial passage 29 closing        cover    -   29 a cylindrical portion 29 b projecting portion for closing        stator inner peripheral passage 29 c smallest gap 30 balancer        cover 30 a inner passage 30 b rotary disk 30 c inner peripheral        flow guide 31 upper balance weight 31 a rotation direction        leading end portion 31 b rotation direction trailing end portion        32 lower balance weight 33 rotator upper end fixing substrate 34        rotator lower end fixing substrate 35 oil separating rotary disk        (single member) 36 oil separating cup 36 a cylindrical lateral        wall    -   36 b bottom plate 36 c oil drain hole 36 d cup inner passage 37        cylindrical lateral wall (single member) 38 balancer fixing        bottom plate 38 a disk portion 38 b stator inner peripheral        passage closing portion 39 oil drain hole 40 centrifugal        impeller 41 vane 42 inner peripheral flow guide 43 vane        superjacent disk 44 vane subjacent disk 46 vane inner passage 47        inter-vane passage 48 vane outer passage 49 rotary pressure        increasing mechanism 50 compression mechanism casing 51 fixed        scroll 52 orbiting scroll 54 sub bearing unit 55 main bearing        unit 56 discharge cover    -   56 a opening portion 57 refrigerant passage 60 compression        mechanism 100 hermetic compressor 101 vapor compression-type        refrigeration cycle device 102 radiator 103 expansion mechanism        104 evaporator

1: A hermetic compressor, comprising: a hermetic container having a bottom portion for storing lubricating oil; an electric motor arranged in the hermetic container, the electric motor including: a stator; and a rotator through which a rotator vent is formed in a vertical direction; a drive shaft attached to the rotator; a scroll-type compression mechanism arranged in the hermetic container, for compressing refrigerant by rotation of the drive shaft and discharging the compressed refrigerant into the hermetic container, a rotary pressure increasing mechanism arranged on an upper portion of the rotator, for increasing a pressure of refrigerant gas flowing from a space below the electric motor through the rotator vent into the rotary pressure increasing mechanism by allowing the refrigerant gas to flow through the rotary pressure increasing mechanism while rotating about the drive shaft, a cylindrical lateral wall for partitioning a space above the electric motor into an outer space on a stator side and an inner space on a rotator side in such a manner that the cylindrical lateral wall surrounds the rotary pressure increasing mechanism; and a discharge pipe communicated to the inner space, for allowing the refrigerant to flow out from the inner space into an external circuit that is external to the hermetic container, the rotary pressure increasing mechanism being configured to make a pressure in the inner space larger than a pressure in the outer space. 2: The hermetic compressor of claim 1, wherein the rotary pressure increasing mechanism comprises a centrifugal impeller that is rotated about the drive shaft so that the refrigerant gas flows into the centrifugal impeller through an inlet on an inner peripheral side, and flows out through an outlet on an outer peripheral side while being increased in pressure. 3: The hermetic compressor of claim 2, wherein the cylindrical lateral wall is arranged to surround the outlet on the outer peripheral side of the centrifugal impeller. 4: The hermetic compressor of claim 2, wherein the centrifugal impeller comprises: a lower surface plate for blocking inflow of the refrigerant gas from a region below vanes of the centrifugal impeller into the centrifugal impeller; an upper surface plate for blocking inflow of the refrigerant gas from a region above the vanes of the centrifugal impeller into the centrifugal impeller; and a partition plate for blocking inflow of the refrigerant gas into the inlet on the inner peripheral side of the centrifugal impeller through passages other than the rotator vents. 5: The hermetic compressor of claim 1, wherein the stator comprises a plurality of electric motor upper coil-interconnecting portions formed of projecting parts of a coil wound around a core, the projecting parts projecting from an upper end of the stator, and wherein the cylindrical lateral wall is interposed to separate the rotary pressure increasing mechanism and the electric motor upper coil-interconnecting portions from each other. 6: The hermetic compressor of claim 1, further comprising a closing member for closing an upper part of a passage formed between the rotator and the stator. 7: The hermetic compressor of claim 1, wherein the cylindrical lateral wall is arranged to an upper end of the rotator, and is rotated together with the rotator. 8: The hermetic compressor of claim 1, wherein the compression mechanism is arranged above the electric motor, and wherein the refrigerant gas that is compressed by the compression mechanism and discharged into the hermetic container flows from the outer space into the space below the electric motor through stator outer peripheral passages formed between the stator and the hermetic container, is moved from the space below the electric motor up to an upper end of the rotator through the rotator vents, flows into the rotary pressure increasing mechanism to be increased in pressure, flows into the inner space to increase the pressure in the inner space, and is discharged to an outside through the discharge pipe while suppressing inflow of the refrigerant gas from the outer space to the inner space. 9: The hermetic compressor of claim 8, further comprising a discharge cover for partitioning a part of the space above the electric motor, which is positioned above the cylindrical lateral wall, into the outer space and the inner space, the discharge cover being arranged under the compression mechanism, wherein the discharge cover and the cylindrical lateral wall are used to increase a passage resistance of a short circuit passage that communicates the outer space and the inner space to each other. 10: A vapor compression-type refrigeration cycle device, comprising: the hermetic compressor of claim 1; a radiator for transferring heat of refrigerant that is compressed by the hermetic compressor; an expansion mechanism for expanding the refrigerant that flows out from the radiator; and an evaporator for causing the refrigerant that flows out from the expansion mechanism to receive heat. 